Study On The Mechanism Of Joint Load-bearing Of Various Sections In A Mine Shaft Tower System

Mine shaft tower structure system consists of superstructure (shaft tower), pile-raft foundations, foundation soil and sidewall, which are jointed load-bearing and influenced each other in outside loading action. But the traditional designing method adopted in engineering field regards the superstructure (shaft tower), pile-raft foundations and foundation soil respectively and calculates them separately. And the joint load-bearing character of pile-raft foundations and sidewall will not be considered. Disregarding the joint load-bearing between them, also disregarding the difference among them could make the internal forces of the superstructure, pile-raft foundations and sidewall not conform to the reality, and the result of the designing method becomes either unsafe or wasted, and leads to economic loss. So it is necessary to study the superstructure (shaft tower), pile-raft foundations, foundation soil and sidewall as a whole.Analysis the characteristic force among the four parts when they joint load-bearing.Optimize shaft tower, pile-raft foundations, and sidewall design. Designed so that the thickness of the raft, the pile diameter and length and the sidewall thickness can meet the requirements of safety and reliably, and can achieve the purpose of saving materials.In this paper, superstructure (shaft tower), pile-raft foundations, foundation soil and sidewall regarded as joint load-bearing of entire system, and we analyze their system with interactive analysis theory. Adopting sub-structure method, analysis the system which consists of superstructure, raft foundations, pile and foundation soil, first the entire structure is separated into a number of sub-structure, and then in accordance with the order of the various sub-structural rigidity and load to agglomerate, thereby realize the entire superstructure of the rigidity and load agglomerate to the raft foundation. Finally regard pile and foundation soil as a pile-soil system and analysis, establish the pile-soil supporting of the bearing system rigidity matrix, then calculated the interaction basic equation of superstructure (shaft tower), pile-raft foundations and foundation soil. By agglomerating and superimposing superstructure rigidity and load to the pile-raft foundations raft-board. At the same time, assume the depth that shaft tower pile-raft foundations impact side wall. Analysis the bearing system of sidewall-pile-soil interaction and raft foundition, then get the interactive displacement equation of the superstructure-sidewall-piled raft system.Foundation soil was adopted the Drucker-Prage subsoil model, pile-soil interface adopt the side to side contact element to treaty, pile-raft foundations adopt thick-plate theory to analysis, establish a structural model. Research it with numerical calculation method, the three-dimensional finite element analysis for shaft tower, pile-raft foundation, foundation soil and sidewall which under vertical load.Analysis shows that pile-raft foundations raft top of the maximum vertical displacement values consistent with the measured values;Pile-raft foundations in the "return" of the four fonts raft interior angle and the pile foundation with a raft connecting the stress concentration, which is due to the changes in section;The maximum tension stress and compressive resistance on the sidewall in the bottom of the sidewall .and gradually reduced from the bottom to the top of sidewall .Consider the four parts joint load-bearing when use numerical value to simulate the pile-raft foundations of the maximum vertical displacement value combined with the measured maximum value proved that the shaft tower, pile-raft foundation, the foundation soil and sidewall as a joint load-bearing whole role to analysis is feasible and necessary.